What's the Best CPAP Humidity Level?

Key Takeaways

• A CPAP humidifier adds warmth and moisture to the air you breathe.
• Heated humidifiers and heated tubing can reduce dry nose and mouth.
• Humidifiers can be adjusted manually, or set to automatically adjust the temperature and moisture levels based on ambient temperature and humidity.

What Is CPAP Humidity?

The pressurized air delivered by CPAP therapy has a tendency to dry out the throat and nasal passages. CPAP humidifiers are designed to gently warm and humidify the air, reducing the potential for discomfort and irritation. 

Earlier humidifiers had a passover design with water chambers that released moisture into the air on its way to the mask. 

In contrast, most modern CPAP machines use heated humidification. A heated humidifier incorporates a water chamber with a hot plate to both humidify and heat the air as it passes through. As with the rest of your CPAP supplies, it’s crucial to keep this water chamber clean and always fill it with distilled water instead of tap water. Tap water contains minerals and bacteria that damage the machine and irritate your airway.

Heated humidifiers draw electricity from the CPAP machine, so they can shorten battery life when traveling and may not be safe to use with an external battery. 

An alternative to the heated humidifier is an in-line or waterless humidifier. In-line humidifiers consist of a small gadget that slots into the tubing and captures water droplets from exhaled breath to rehumidify the air you breathe in. These components are especially common with travel CPAP machines. 

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Why Are CPAP Humidity Levels Important?

CPAP humidity levels are important because high-speed air from the CPAP machine feels drier and cooler than the air we normally breathe. A CPAP humidifier helps reduce common side effects commonly caused by CPAP air, such as a dry mouth, dry nose, nosebleeds, and sore throat.

One small problem with using a humidifier is that when warm, humid CPAP air passes through the tubing, it comes into contact with cooler temperatures from the bedroom air, which can cause condensation to form. Water droplets can form and drip into the mask. That’s why a humidifier is often used together with heated tubing, which minimizes the temperature shock to prevent excessive condensation. 

Heated humidification and heated tubing may also help if CPAP therapy is giving you a stuffy or runny nose, although sometimes nasal congestion needs to be addressed directly with nasal spray.

Since it’s designed to make CPAP therapy more comfortable, some research suggests that using a humidifier may help CPAP users meet their compliance requirements – though results from clinical studies are mixed. 

Ultimately, whether or not to use a CPAP humidifier is a personal choice. As it’s fairly low-risk, most experts recommend trying a humidifier if you think it would benefit you. Humidification may be particularly helpful for those with nasal congestion or who have previously had throat surgery to correct an obstructed airway. Individuals who live in dry climates also benefit from humidified air via CPAP.

What Is the Best CPAP Humidity Level?

There’s no ideal CPAP humidity level that works for everybody. Rather, the best CPAP humidity level depends on your bedroom temperature and humidity levels, as well as other factors like your machine’s air pressure settings. You may find you need to adjust your CPAP humidity settings as the seasons change or when you travel.

People who live in a dry climate, such as the southwest U.S., often need stronger humidity settings. In winter, both the cold weather and indoor heating can dry out ambient air.

Signs Your CPAP Humidity Is Too Low

Your CPAP humidity might be too low if you experience side effects related to dry air, such as:

• Nasal congestion
• Dry nose or nosebleeds
• Dry mouth 
• Sore throat or hoarse voice
• Sinus pain
• Headache
• Reduced sense of smell

Signs Your CPAP Humidity Is Too High

Setting the humidity too high on your CPAP machine may also lead to uncomfortable side effects.When the humid CPAP air passes through the tubing, it can cause tiny water droplets to condense along the sides of the tubing, sometimes dripping into the nose or mouth. This effect is called rainout, and it’s caused by the temperature difference between the CPAP air and the room temperature. 

While some rainout is normal, you can reduce excessive rainout by using heated tubing, increasing the temperature of your bedroom, or easing up on the humidifier’s settings.

Keep in mind that side effects like a dry mouth can also be due to unrelated factors such as mask leak. If you’ve tried changing your humidity settings and you’re not having any luck, talk to your doctor.

How to Adjust Your CPAP Humidity Level

Humidifiers usually allow you to set the temperature and preferred humidity manually using a touchscreen, a smartphone app, or a dial. Many humidifiers and heated tubes also automatically adjust humidity and temperature settings based on the conditions in your bedroom.

The exact process varies between machines, but most CPAP humidifiers offer multiple settings and allow you to switch between them using the same technology. Unlike the pressure settings, the humidity settings can be adjusted by the user themselves rather than a medical professional.

1. Navigate to the humidifier’s settings menu.
2. Choose between Auto and Manual. If you’ve chosen Auto, your work is done. The humidifier will track changes in the room temperature and humidity, and self-adjust throughout the night.
3. If you’ve chosen Manual, select your desired temperature and humidity level. Manufacturers will have set an arbitrary neutral temperature and humidity, but you can change it until you find the ideal humidity for you. The humidity level is usually listed on a scale, with higher numbers being the most humid. For example, on a scale of 1 to 8, 8 would be the most humid. 
4. If applicable, navigate to the heated tubing menu and select your desired temperature.

If you prefer to use the manual mode instead of the auto mode, it’s best to adjust the settings in small increments over several nights until you find the temperature and humidity that work for you. You also have the option of turning off the humidifier completely.

Since each interface is a little different, you should check your user guide or the manufacturer’s how-to videos for explicit instructions on how to use your humidifier model.